Buggy code:
public class CastExpression extends Expression { public Expression expression ; public Expression type ; public boolean needRuntimeCheckcast ; public TypeBinding castTb ; public CastExpression ( Expression e , Expression t ) { } public FlowInfo analyseCode ( BlockScope currentScope , FlowContext flowContext , FlowInfo flowInfo ) { } public final void areTypesCastCompatible ( BlockScope scope , TypeBinding castTb , TypeBinding expressionTb ) { needRuntimeCheckcast = false ; if ( ( castTb == null ) || ( expressionTb == null ) ) return ; if ( castTb . isBaseType ( ) ) { if ( expressionTb . isBaseType ( ) ) { if ( expressionTb == castTb ) { constant = expression . constant ; return ; } if ( ( scope . areTypesCompatible ( expressionTb , castTb ) ) || ( BaseTypeBinding . isNarrowing ( castTb . id , expressionTb . id ) ) ) { expression . implicitConversion = ( ( castTb . id ) << 4 ) + ( expressionTb . id ) ; if ( ( expression . constant ) != ( Constant . NotAConstant ) ) constant = expression . constant . castTo ( expression . implicitConversion ) ; return ; } } scope . problemReporter ( ) . typeCastError ( this , castTb , expressionTb ) ; return ; } if ( expressionTb == ( NullBinding ) ) return ; if ( expressionTb . isBaseType ( ) ) { scope . problemReporter ( ) . typeCastError ( this , castTb , expressionTb ) ; return ; } if ( expressionTb . isArrayType ( ) ) { if ( castTb . isArrayType ( ) ) { TypeBinding expressionEltTb = ( ( ArrayBinding ) ( expressionTb ) ) . elementsType ( scope ) ; if ( expressionEltTb . isBaseType ( ) ) { if ( ( ( ( ArrayBinding ) ( castTb ) ) . elementsType ( scope ) ) == expressionEltTb ) needRuntimeCheckcast = true ; else scope . problemReporter ( ) . typeCastError ( this , castTb , expressionTb ) ; return ; } areTypesCastCompatible ( scope , ( ( ArrayBinding ) ( castTb ) ) . elementsType ( scope ) , expressionEltTb ) ; return ; } else if ( castTb . isClass ( ) ) { if ( scope . isJavaLangObject ( castTb ) ) return ; } else { if ( ( scope . isJavaLangCloneable ( castTb ) ) || ( scope . isJavaIoSerializable ( castTb ) ) ) { needRuntimeCheckcast = true ; return ; } } scope . problemReporter ( ) . typeCastError ( this , castTb , expressionTb ) ; return ; } if ( expressionTb . isClass ( ) ) { if ( castTb . isArrayType ( ) ) { if ( scope . isJavaLangObject ( expressionTb ) ) { needRuntimeCheckcast = true ; return ; } } else if ( castTb . isClass ( ) ) { if ( scope . areTypesCompatible ( expressionTb , castTb ) ) return ; if ( scope . areTypesCompatible ( castTb , expressionTb ) ) { needRuntimeCheckcast = true ; return ; } } else { if ( ( ( ReferenceBinding ) ( expressionTb ) ) . isFinal ( ) ) { if ( scope . areTypesCompatible ( expressionTb , castTb ) ) return ; } else { needRuntimeCheckcast = true ; return ; } } scope . problemReporter ( ) . typeCastError ( this , castTb , expressionTb ) ; return ; } if ( castTb . isArrayType ( ) ) { if ( ( scope . isJavaLangCloneable ( expressionTb ) ) || ( scope . isJavaIoSerializable ( expressionTb ) ) ) needRuntimeCheckcast = true ; else scope . problemReporter ( ) . typeCastError ( this , castTb , expressionTb ) ; return ; } else if ( castTb . isClass ( ) ) { if ( scope . isJavaLangObject ( castTb ) ) return ; if ( ( ( ReferenceBinding ) ( castTb ) ) . isFinal ( ) ) { if ( ! ( scope . areTypesCompatible ( castTb , expressionTb ) ) ) { scope . problemReporter ( ) . typeCastError ( this , castTb , expressionTb ) ; return ; } } } else { <START_BUG> if ( ( castTb != expressionTb ) && ( ( scope . compareTypes ( castTb , expressionTb ) ) == ( NotRelated ) ) ) { <END_BUG> MethodBinding [ ] castTbMethods = ( ( ReferenceBinding ) ( castTb ) ) . methods ( ) ; MethodBinding [ ] expressionTbMethods = ( ( ReferenceBinding ) ( expressionTb ) ) . methods ( ) ; int exprMethodsLength = expressionTbMethods . length ; for ( int i = 0 , castMethodsLength = castTbMethods . length ; i < castMethodsLength ; i ++ ) for ( int j = 0 ; j < exprMethodsLength ; j ++ ) if ( ( castTbMethods [ i ] . returnType ) != ( expressionTbMethods [ j ] . returnType ) ) if ( ( castTbMethods [ i ] . selector ) == ( expressionTbMethods [ j ] . selector ) ) if ( castTbMethods [ i ] . areParametersEqual ( expressionTbMethods [ j ] ) ) scope . problemReporter ( ) . typeCastError ( this , castTb , expressionTb ) ; } } needRuntimeCheckcast = true ; return ; } public void generateCode ( BlockScope currentScope , CodeStream codeStream , boolean valueRequired ) { } public TypeBinding resolveType ( BlockScope scope ) { } public String toStringExpression ( ) { } public void traverse ( IAbstractSyntaxTreeVisitor visitor , BlockScope blockScope ) { } }

Fix:
if ( ( castTb != expressionTb ) && ( ( Scope . compareTypes ( castTb , expressionTb ) ) == ( NotRelated ) ) ) {